1. Field of the Invention
This invention relates in general to engines and in particular to intermittent detonation engines fueled by a liquid fuel in which the detonation products are used as the thrust producing medium.
2. Description of Related Art
A pulse detonation engine is an apparatus which produces a high pressure exhaust from a series of repetitive detonations within a detonation chamber. A fuel is detonated within the chamber, causing a wave which propagates at supersonic speeds. The speeds could approach or exceed Chapman Jouguet detonation velocities. The wave compresses the fluid within the chamber, increasing its pressure, density, and temperature. As the wave passes out an open rearward end of the detonation chamber, thrust is created. The cycle is then repeated.
At high speeds, such as Mach 2 to about Mach 3.5, such an engine would be theoretically more efficient than conventional turbojets because the engine does not require compressors or turbines. A pulse detonation engine supplying the same amount or more of thrust as a conventional gas turbine engine would theoretically weigh less. Also, a pulse detonation engine could be used as a propulsion system for a rocket.
Typically, pulse detonation engines have been described as gaseous fueled engines. Most aircraft today are fueled by liquid hydrocarbons such as JP-4, JP-5, or JP-10. Significant infrastructures are installed on these aircraft to store and deliver the liquid fuel to the aircraft""s power source. Because of this, it highly desirous to have a pulse detonation engine that is fueled by liquid fuel and that can be easily integrated for use on an existing aircraft that uses liquid fuel.
The pulse detonation engine of the present invention solves the main problem associated with integrating a pulse detonation engine with an existing aircraft. Since the pulse detonation engine of the present invention uses liquid fuel as a propellant, the engine can be easily integrated with an existing aircraft design, using the traditional liquid fuel infrastructure of the existing aircraft.
In a first embodiment of the present invention, a pulse detonation engine includes an outer tubular housing having a cylindrical bore and a plurality of outer housing ports. An inner tubular housing having a cylindrical bore and plurality of inner housing ports is rigidly and concentrically connected within the outer tubular housing. A detonation chamber is formed in the annulus between the inner and outer housings, the detonation chamber having an upstream end wall and an open downstream end.
An outer valve sleeve having a plurality of outer sleeve ports is concentrically and rotatably mounted to an exterior of the outer housing, the outer sleeve ports aligning with the outer housing ports when the outer valve sleeve is in an open position and not aligning with the outer housing ports when the outer valve sleeve is in a closed position.
A plurality of fuel injectors for injecting liquid fuel into the detonation chamber are rigidly disposed in the inner tubular housing, each fuel injector aligning with one of the inner housing ports. An inner protective sleeve having a plurality of inner sleeve ports is concentrically carried on an exterior of the inner housing. The inner protective sleeve oscillates along a longitudinal axis of the inner tubular housing between an open position and a closed position, the inner sleeve ports aligning with the inner housing ports when the inner protective sleeve is in the open position and not aligning with the inner housing ports when the inner protective sleeve is in the closed position.
An external drive system is used to rotate the outer valve sleeve and oscillate the inner protective sleeve. As the outer valve sleeve opens, air enters the detonation chamber through the outer housing ports. At the same time, the inner protective sleeve opens, and the fuel injectors inject liquid fuel into the detonation chamber through the inner housing ports. The liquid fuel and air form a fuel mixture, which is detonated by igniters that are disposed in the upstream end wall. The resulting detonation wave discharges out of the open downstream end of the detonation chamber, creating thrust for the engine.
In a second embodiment, a pulse detonation engine includes an outer tubular housing having a cylindrical bore and a plurality of outer housing ports. An inner tubular housing having a cylindrical bore and plurality of inner housing ports is rigidly and concentrically connected within the outer tubular housing. A detonation chamber is formed in the annulus between the inner and outer housings, the detonation chamber having an upstream end wall and an open downstream end.
An inner valve sleeve having a plurality of inner sleeve ports is concentrically and rotatably mounted to an interior of the inner housing, the inner sleeve ports aligning with the inner housing ports when the inner valve sleeve is in an open position and not aligning with the inner housing ports when the inner valve sleeve is in a closed position.
A plurality of fuel injectors for injecting liquid fuel into the detonation chamber are rigidly disposed on the outer tubular housing, each fuel injector aligning with one of the outer housing ports. An outer protective sleeve having a plurality of outer sleeve ports is concentrically mounted to an interior of the outer housing. The outer protective sleeve oscillates along a longitudinal axis of the outer tubular housing between an open position and a closed position, the outer sleeve ports aligning with the outer housing ports when the outer protective sleeve is in the open position and not aligning with the outer housing ports when the outer protective sleeve is in the closed position.
An external drive system is used to rotate the inner valve sleeve and oscillate the outer protective sleeve. As the inner valve sleeve opens, air enters the detonation chamber through the inner housing ports. At the same time, the outer protective sleeve opens, and the fuel injectors inject liquid fuel into the detonation chamber through the outer housing ports. The liquid fuel and air form a fuel mixture, which is detonated by igniters that are disposed in the upstream end wall. The resulting detonation wave discharges out of the open downstream end of the detonation chamber, creating thrust for the engine.